Calf age does not affect test sensitivity or specificity for detection of BVD virus in New Zealand
Bovine virus diarrhea virus (BVDV) is a common viral infection which results in immunosuppression, gastrointestinal disease, and impaired fertility. Where cattle are less than 150 d pregnant and are exposed to the virus, the fetus may become persistently infected (PI) resulting in lifetime shedding of the virus. Control strategies include testing and removing PI calves based on testing ear-notch tissue samples to minimize the risk of false negative results associated with persistence of maternal antibodies.
This study aimed to define the prevalence at herd and calf level amongst 6-week-old calves from herds that had evidence of BVDV in the lactation preceding the calves’ birth. The objective of this study was to assess test sensitivity when calves are tested at <35 days of age.